2, 5-di-[1&#39;, 3&#39;, 4&#39;-oxdiazol-2-yl]thiophene compounds



United States Patent 3,184,468 2,5-Dl-[1',3,4-0XDIAZOL-2-YL]'IHOPHENE COMPOUNDS Adolf Emil Siegrist and Leonardo Guglielmetti, Basel,

Erwin Maeder, Munchenstein, and Peter Liechti, Binningen, Switzerland, assignors to Cilia Limited, Basel, Switzerland, a company of Switzerland No Drawing. Filed Apr. 23, 1963, Ser. No. 274,943 Claims priority, application Switzerland, May 4, 1962,

Claims. (Cl. 260-307) The present invention provides new 2:5-di-[1':3:4- oxdiazolyl-(Z')l-thiophene compounds corresponding to the formula n u i N-N s N where A and A are identical or difierent and each represents a monocyclic radical of aromatic character, for example a pyridine, furan or thiophene radical, and more especially a benzene radical.

The symmetrical compounds of the Formula 1 are obtained by treating an acylhydrazine of the formula (2) o 0'11 0 o A C/ E i H1{\T--NH S EN NH Where the two As represent identical radicals of the kind defined above-with an agent capable of eliminating water.

The symmetrical acylhydrazines of the Formula 2, in their turn, are obtained by reacting thiophene-ZzS-dicanboxylic acid dihydrazide of the formula (3) o HO-CH o HgN-NH S N H-N Hg in the molecular ratio of 1:2 with a monocarboxylic acid chloride of the formula (4) A-CO-Cl or by reacting thiophene-Zz5-dicarhoxylic acid dichloride of the formula with a monocarhoxylic acid hydrazide of the formula (6) ACO-NHNH The radical A in the monocanboxyiic acid derivatives of the kind defined above is a monocyclic radical of aromatic character, for example, a pyridine, furan or thio phene radical, and more especially a benzene radical. In the latter case preferred use is made of chlorides or hydrazides of benzenemonocarboxylic acids of the formula Y: where Y, stands for a hydrogen or chlorine atom or for an alkyl or an alkoxy radical, and Y for a hydrogen or chlorine atom or for an alkyl radical. The alkyl and allcoxy radicals contain with advantage 1 to 8 carbon atoms.

As examples of carboxylic acids of the formula A-COOH, whose halides or hydrazides are suitable as starting materials for the manufacture of the acylhydrazines of the Formula 2, there may be mentioned:

Benzenecarboxylic acids of the formula Where Z stands for a hydrogen atom, an alkyl group with 1 to 8 carbon atoms, an alkoxy group with 1 to 8 carbon atoms, or a chlorine atom, such as:

Thiophenecarboxylic acids such as Thiophene-Z-carboxylic acid,

3- or 5-methylthiophene-Z-carboxylic acid,

3 :5-dirnethylthiophene-Z-canboxylic acid, and Thiophene-Z S-dicanboxylic acid.

The reactions required in the manufacture of the symmetrical dioXdiazolyl-thiophene compounds of the Formula 1 and of the starting materials of the Formula 2. may be performed in the conventional manner. Thus, the reaction of the acid chlorides with the acid hydra- ZldES is advantageously conducted in the presence of acidbinding agents, for example in a pyridine base, such as picoline or pyridine itself.

A very suitable agent capable of eliminating water for use in the conversion of the acylhydrazines of the Formula 2 into the symmetrical dioxdiazolyl-thiophene compounds of the Formula 1, is thionylchloride, inter alia, because it is possible to perform the cyclization in an excess of this water-eliminating agent (which, at the same time, acts as solvent), whereupon any unconsumed thionylchloride is easy to eliminate.

The asymmetrical dioxdiazolyl-thiophene compounds of the Formula l-that is to say compounds in which A and A diiier from each other, each representing a monocyclic radical of aromatic character, for example a pyridine, furan or thiophene radical0r more especially a benzene residueare obtained by treating a diacylhydrazine of the formula (9) O C H O 0 Patented May 18, 1965 .3 with an agent capable of eliminating water, more especially with thionylchloride.

To prepare the diacylhydrazines of the Formula 9, a monocarboxylic acid hydrazide of the formula is reacted with thiophene-+2:S-dicarboxylic acid monomethyl ester chloride of the formula in the presence of an organic solvent, for example chlorobenzene; the resulting acylhydrazine of the formula l ke NHHN OCH;

is treated with a water-eliminating agent, more. especially with thionylchloride, optionally after first having been isolated; in the oxidaZolyl-thiophene compound of the formula the carboxylic acid methyl ester group attached to the thiophene residue is converted into a carboxylic acid hydrazide group, and the monoacylhydrazine of the formula is condensed with a monocarboxylic acid chloride of the formula where X and X are identical or diiferent and each represents a group of the formula where Z represents a hydrogen atom or a carboxyl or carbomethoxy group-or a benzene radical of the formula where Y stands for a hydrogen or chlorine atom or an 4 alkyl or alkoxy radical which preferably contains 1 to 8 carbon atoms, and Y stands for a hydrogen or chlorine atom or an alkyl group with up to 8 carbon atoms.

The new 2:5-di-[l:3':4'-oxdiazolyl (2')] thiophene compounds of the Formula 1 may be used for optically brightening a wide variety of organic materials. Particularly good brightening effects are obtained when these thiophene compounds are incorporated with materials from polyvinyl chloride, from polyolefins (such, for example, as polyethylene or polypropylene), from polyesters or from polyamides.

The new thiophene derivatives can be added to, or incorporated with, the materials to be treated before or during their shaping. Thus, in the manufacture of films, foils, tapes or mouldings they may be added to the moulding composition or they may be dissolved or finely dis persed in the spinning solution. The new thiophene derivatives may also be added before or during the polycondensation yielding, for example, polyamides or polyesters, to the reaction mixture, or before or during the polymerisation of monomers, for example vinyl chloride or acrylonitrile, to the polymerisation batch.

The amount of new thiophene compound to be used, calculated on the weight of the material to be optically brightened, may vary Within wide limits. Even a very small amountin certain cases, for example, as little as 0.0l%will produce a distinct and durable brightening effect. An amount of over 3% will, in general, not prove harmful, but it does not offer any advantage over the normal amount. 7

Unless otherwise indicated, parts and percentages in the following examples are by weight.

EXAMPLE 1 10.2 parts of the bis-diacylhydrazine of the formula HO-CH N H-HN (obtained by reacting 2 molecular proportions of benzoyl chloride with 1 molecular proportion of thiophene-2:5- dicarboxylic acid dihydrazide in pyridine) in parts by volume of thionyl chloride are heated within 30 minutes to the boil while being stirred, and the batch is then refluxed for 3 to 4 hours. When hydrochloric acid is no longer being evolved, the excess of thionyl chloride is removed by distillation from the clear, light-yellow reaction solution, initially under atmospheric pressure and finally under vacuum. The residue is triturated with water in a mortar, suction-filtered, washed with water and dried, to yield about 9.0 parts (=96.8% of the theoretical yield) of the thiophene compound of the formula 0) O\ HC-CH O @4 at it rt 5 ii in the form of a light-yellow powder melting at 255 to 259 C. After three recrystallisations from dimethylformamide with the aid of active carbon, there are obtained almost colourless, very fine needles which display a strong pale-blue fluorescence in ultraviolet light and melt at 269270 C.

Analysis.C H O N S. Molecular weight: 372.41. Calculated: C, 64.50; H, 3.25; N, 15.04. Found: C, 64.31; H, 3.39; N, 14.81.

The following Table I lists further oxidiazolyl-thiophene compounds which are accessible by the process described above.

The compounds of the Formulae 22 to 34 are very suitable for optically brightening foils from, for example, polyvinyl chloride or polyethylene.

7 EXAMPLE 2 10.5 parts of the hydrazine of the formula O HC-CH O CH3 O G K C-Q-(B-OH l I-lul s NHHN (JHa in 100 parts by volume of thionyl chloride are heated within 30 minutes to the boil while being stirred, and the batch is then refluxed for 3 to 4 hours. When hydrochloric acid is no longer being evolved the excess of thionyl chloride is removed by distillation under vacuum from the clear, pale-yellow reaction solution. The residue is mixed with 100 parts of alcohol and suctioned, to yield 9.2 parts (=91.5% of the theoretical yield) of the thiophene compound of the formula (36) 0 HG---OH 0 CH3 QC C J )C C( JCl1 It .t t t... in the form of a light-yellow powder melting at 220 to 222 C. After three recrystallisations from dioxane with the aid of active carbon, there are obtained pale-yellow fine needles which display a strong greenish blue fluorescence in ultraviolet light and melt at 223224 C.

Analysis.C H O N S. (Molecular weight 428.51.) Calculated: C, 67.27; H, 4.70; N, 13.07. Found: C, 67.60; H, 4.83; N, 13.31.

The following Table 11 lists further oxdiazolyl-thiophene compounds which are accessible by the process described above.

The hydrazine of the Formula 35 used as starting material can be prepared in the following manner:

A mixture of 37.2 parts of thiophene-Z:S-dicarboxylic acid monomethyl ester (prepared as described in Example VIIa of US. Patent No. 2,680,731 to E. I. du Pont de Nemours and Company, patented June 8, 1954), 250 parts by volume of chlorobenzene and 30 parts of thionyl chloride is stirred and heated for 1 hour to 115 C. and then further stirred for another hour at 115 C., whereupon thiophene-Z:S-dicarboxylic acid monomethyl ester chloride forms and a complete solution is obtained. After having removed the excess of thionyl chloride by passing through dry air or by vacuum distillation, 27.2 parts of benzoic acid hydrazide and 250 parts by volume of chlorobenzene are added at 20 C. The reaction mixture is then heated in 1 to 1% hours to the boil while being vigorously stirred and then refluxed for 6 to 12 hours, whereupon the colourless hydrazide of the formula NH-HN s 00H; precipitates. When hydrochloric acid is no longer being evolved, 60 parts of thionyl chloride are dropped in within 30 minutes, and the reaction mixture is refluxed for 4 to 8 hours with exclusion of air. The excess thionyl chloride and the bulk of chlorobenzene are then distilled off the resulting clear reaction solution. During the following cooling to about 10 C., 250 parts by volume of methanol are added. The crystalline precipitate, the 5- [5' phenyl (1") 1:3:4' -'oxdiaZolyl-(2')]-thi0phene- 2-carboxylic acid methyl ester of the formula is suctioned off, washed. with 250 parts by volume of methanol, and dried, to yield about 53.6 parts (=93.8% of the theoretical yield) of a pale-yellow crystalline powder melting at 161.5 to 162 C. After three recrystallisations from dioxane-t-water (4:1) with the aid of active carbon and fullers earth, an almost colourless, fine crystalline powder is obtained which melts at 164-1645 C.

Analysis.C H O N S. (Molecular weight 286.31.) Calculated: C, 58.73; H, 3.52; N, 9.78. Found: C, 58.66; H, 3.75; N, 9.83.

28.6 parts of 5-[5'-phenyl-(1")-1':3':4-oxdiazolyl- (2')]-thiophene-2-carboxylic acid methyl ester of the Formula 38 are dissolved with heating in 200 parts by volume of dioxane. 25 parts of hydrazine hydrate are added to the solution and the batch is stirred with reflux for 15 hours, whereupon 5-[5'-phenyl-(1)-1:3':4'-oxdiazolyl-(Z)]-thiophene-2-carboxylic acid hydrazide of the formula gradually settles out in the form of fine needles. The reaction mixture is diluted with 100 parts by volume of methanol, cooled to about 5 C., suctioned and the filter residue is rinsed with 120 parts by volume of methanol cooled to 5 C. After drying, there are obtained about 25.2 parts (=88% of the theoretical yield) of paleyellow, fine needles melting at 228-2295 C.

Analysis.-C H O N S. (Molecular weight 286.31.) Calculated: C, 54.54; H, 3.52; N, 19.57. Found: C, 54.51; H, 3.57; N, 19.27.

7.2 parts of 5-[5'-phenyl-(1")-1':3:4-oxdiazolyl-(2')] thiophene-2-carboxylic acid hydrazide of the Formula 39 are stirred in parts by volume of pyridine at room temperature. 5.4 parts of para-tertiary butylbenzoyl chloride are then dropped in within 45 minutes at 20 to 25 C.; the batch is stirred for another 45 minutes at this temperature, then heated within one hour to -90 C. and the yellow, slightly turbid reaction solution is stirred on for 3 hours at this temperature, then cooled to room temperature and stirred into 3000 parts of cold water. The precipitated reaction product is suctioned oflf, washed with cold water and then with hot water and dried. Yield: about 11 parts (=99% of the theoretical) of the hydrazine of the Formula 35 in the form of a pale-yellow powder which melts at 223 to 225 C.

Table II i T t i-\ M r N--N S N-N Analysis 3 Yleldlll D t! Mglgls at ercen escrp on No 2 p Calculated Found (mols) OCHa 97 Pa1e-ye1low,fine,ielted 249-250.. 0; 62.68... c: 62.24. needles (dioxane). H: 3.51".-- H: 3.64. N: 13.92 N: 14-09. i 9 (402.43) 41 O(CHz)7-CH5 84 Almost colourless, veryfine 214 215.. 0: 67.18 0:66.77. needles (methylenechloride H: 564.-- H: 5.70. ethanol). N: 11.19 N: 11.09.

Table lI-Continued /O\ HCCH tr l S 1-l ll Analysis Yield in Melts at No. R R percent Description 0.

Calculated Found (mols) i 4.2.- GCH 0 CH; 93 Pale-yellow, very fine needles 268-269.- C: 65.49.-- C: 65.65. (dioxane). H: 4.84--- H: 4.90. CH N: 12.22 N: 12.46.

(458.54) i 43-.-- QC-Ofla O (CH2)1CH3 92 Pale yellow, shiny needles 199 C: 69.04.--" C: 69.07. (dloxane). H: 6.52"- H: 6.60. CH N: 10.06 N: 10.02.

(556.73) 44. OGH -O (CHM-CH3 92 Light-yellow, very fine 242213.. 0: 65.64... C: 65.50. crystals (dioxane). H: 5.70 H: 5.72. N: 10.56"-.. N: 10.67.

HC-CH O l! ll 45-.-- 0 O8 88 Light-yellow, very fine 267-268.. C: 55.04... C: 54.76. needles (dloxane). H: 2.77- H: 2.77. S OCH: N: 12.84 N: 12.83.

(436.47) CH8 HC-CH O i it ll 46-- COH3 -O O 82 do 280-281.. C: 58.52 C: 58.52. H: 4.09-- H: 4.10. CH3 S OCH: N: 11.37 N: 11.33.

GCH 0 ll ll 47--.- OCH: 0 C0 93 Yellowish, fine, crystal 284 C: 54.07... C: 54.28 powder (chlorobenzenc). H: 3.03 H: 3.00 S OCH: N: 12.01 N: 11.93

(466.49) H(]? %H 48"-- Q C C-COOH 84.5 Pale-yellow,very fine crystals 318-319.. C: 54.02"... 0: 53.80. dioxane). H: 2.39 H: 2.39. S N: 13. N: 13.23.

(422.44) H("]-]GlH 49.-" OCH3 C C-COOH 99 Yellow, very fine needles 32032l C: 53.09... C: 53.32. (dimethylformamide). H: 2.67 H: 2.47. S N: 12.38 N: 12.47.

EXAMPLE 3 tion) and parts of the compound of the Formula 48 or 100 parts of polyvinyl chloride, 54 parts of dioctylphthalate, 2 parts of titanium dioxide and 0.2 part of the thiophene compound of the Formula 27 are carefully mixed and rolled on a calender at 150 to 160 C. to form a foil.

The polyvinyl chloride foil obtained in this manner has a considerably higher white content than a foil that does not contain the thiophene compound.

EXAMPLE 4 10,000 parts of a polyamide in chip form, prepared in known manner from hexamethylenediamine adipate, are mixed with parts of titanium dioxide (rutile modifica- 49 in a tumbler for 12 hours. The chips treated in this manner are then melted in a vessel heated with oil or diphenyl vapour to 300 to 310 C. (after having displaced the atmospheric oxygen with superheated steam) and stirred for /2 hour. The melt is then expressed under a nitrogen pressure of 5 atmospheres (gauge) through a spinning nozzle and the resulting filament is cooled and wound on a spinning bobbin. The resulting filaments have an excellent brightening elfect which is stable to wards heat-setting and has good fastness to washing and light.

EXAMPLE 6 What we claim is: 1. A compound of the formula 0 HG---|CH o x-o 0 ii c-xi wherein X and X each represents a member selected 3. The compound of the formula from the group consisting of H30 0 CH3 H;C( JC oi-o C-Qo-Om (1) f- R I I! it ll it I CH 1130 N- s CH;

\ 4. The compound of the formula 0 HO---CH 0 HCCH 2 HC -CH a 7 a Q? at )H 1 iN s I i'-N s (3) fi 5. The compound of the formula v 0 C-COOH 0 HC-CH 0 it w r (4) 'H( H 1 i-N s 1-i-N 7 /C CO O alkyl I References Cited by the Examiner UNITED STATES PATENTS and 2,689,855 9/ 54 Wagner 260-329 2,765,304 \10/56 Siegrist et al. 260-307 (5) Y1 2,791,563 5/57 Huey -2-3011 8,005,779 10/61 Ackermann et al 2 52-30*1.2 3,065,238 I l/62 Weidinger et al. 260-307 Y 25 3,098,848 7/63 Braus et a1 260329 FOREIGN PATENTS wherein Y is a member selected from the group conslsz- 196,343 3/518 Austria. ing of hydrogen, chlorine, alkyl and alkoxy, and Y is a 835,891 5/60 Great Britain.

member selected from the group consisting of hydrogen, chlorine and alkyl.

2. The compound of the formula I OTHER REFERENCES Richters Organic Chemistry, vol. IV (New York, 1947), pages 14-15. 0 HC-CH o Ll IL @0015 NICHOLAS S. RIZZO, Primary Examiner. U; L M. A. BRINDISI, WALTER A. MODANCE, Examiners. 

1. A COMPOUND OF THE FORMULA 